CVE-2026-86435

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-07. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Footnote extension that fails to deduplicate footnote definitions. Attackers can craft documents with duplicate footnote definitions and references to create quadratic output expansion, consuming excessive memory and CPU to exhaust server resources.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
21%
KEV
Not listed

Published

September 7, 2026

Last Modified

September 9, 2026

Advisory Details (2)

Auto-updated Sep 7, 2026
Patch available. Sources: github.
generic

commonmark 1.5.0 before 2.8.4 Denial of Service via Footnote | Advisories | VulnCheck

https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.8.4-denial-of-service-via-footnote
github Patch Available

Denial of service via duplicate footnote definitions · Advisory · thephpleague/commonmark · GitHub

https://github.com/thephpleague/commonmark/security/advisories/GHSA-jfm3-95jq-q3rf

Vendor Advisories for CVE-2026-86435(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
php-league-commonmark2.10.0-1 ... 2.9.0-1 (23 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
php-league-commonmark2.10.0-1 ... 2.9.0-1 (11 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
php-league-commonmark2.7.0-1 ... 2.8.3-1 (8 versions)2.9.0-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 28× in last 7d / 52× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-19 09:02 UTCGHSA enrichment
  2. 2026-09-18 21:22 UTCEG score recompute
  3. 2026-09-18 21:22 UTCGHSA enrichment
  4. 2026-09-18 19:28 UTCEPSS rescore
  5. 2026-09-18 09:43 UTCGHSA enrichment
  6. 2026-09-17 22:03 UTCEG score recompute
  7. 2026-09-17 22:03 UTCGHSA enrichment
  8. 2026-09-17 19:32 UTCEPSS rescore
  9. 2026-09-17 10:23 UTCGHSA enrichment
  10. 2026-09-16 22:43 UTCEG score recompute
  11. 2026-09-16 22:43 UTCGHSA enrichment
  12. 2026-09-16 14:09 UTCEPSS rescore
  13. 2026-09-16 11:02 UTCEG score recompute
  14. 2026-09-16 11:02 UTCGHSA enrichment
  15. 2026-09-16 05:15 UTCEPSS rescore
  16. 2026-09-15 23:22 UTCGHSA enrichment
  17. 2026-09-15 11:31 UTCEG score recompute
  18. 2026-09-15 11:31 UTCGHSA enrichment
  19. 2026-09-15 03:12 UTCEPSS rescore
  20. 2026-09-15 03:12 UTCEPSS rescore
  21. 2026-09-14 23:51 UTCGHSA enrichment
  22. 2026-09-14 12:11 UTCGHSA enrichment
  23. 2026-09-14 00:31 UTCEG score recompute
  24. 2026-09-14 00:31 UTCGHSA enrichment
  25. 2026-09-13 12:51 UTCGHSA enrichment
Show 27 more
  1. 2026-09-13 01:11 UTCEG score recompute
  2. 2026-09-13 01:11 UTCGHSA enrichment
  3. 2026-09-12 13:31 UTCGHSA enrichment
  4. 2026-09-12 01:51 UTCEG score recompute
  5. 2026-09-12 01:51 UTCGHSA enrichment
  6. 2026-09-11 14:53 UTCEPSS rescore
  7. 2026-09-11 14:53 UTCEPSS rescore
  8. 2026-09-11 14:11 UTCEG score recompute
  9. 2026-09-11 14:11 UTCGHSA enrichment
  10. 2026-09-11 02:31 UTCGHSA enrichment
  11. 2026-09-10 14:51 UTCEG score recompute
  12. 2026-09-10 14:51 UTCGHSA enrichment
  13. 2026-09-10 03:11 UTCGHSA enrichment
  14. 2026-09-09 15:31 UTCEG score recompute
  15. 2026-09-09 15:31 UTCGHSA enrichment
  16. 2026-09-09 14:46 UTCEG score recompute
  17. 2026-09-09 14:46 UTCGHSA enrichment
  18. 2026-09-09 07:52 UTCEG score recompute
  19. 2026-09-09 07:52 UTCGHSA enrichment
  20. 2026-09-08 22:01 UTCEPSS rescore
  21. 2026-09-08 20:13 UTCGHSA enrichment
  22. 2026-09-08 12:50 UTCGHSA enrichment
  23. 2026-09-08 01:07 UTCEG score recompute
  24. 2026-09-08 01:07 UTCGHSA enrichment
  25. 2026-09-07 13:27 UTCEG score recompute
  26. 2026-09-07 12:57 UTCEG score recompute
  27. 2026-09-07 12:56 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-86435?
CVE-2026-86435 is a high vulnerability published on September 7, 2026. commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Footnote extension that fails to deduplicate footnote definitions. Attackers can craft documents with duplicate footnote definitions and references to create quadratic output expansion, consuming excessive…
When was CVE-2026-86435 disclosed?
CVE-2026-86435 was first published in the National Vulnerability Database on September 7, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-86435 actively exploited?
CVE-2026-86435 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 79.4% of all scored CVEs.
What is the CVSS score of CVE-2026-86435?
CVE-2026-86435 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-86435?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-86435, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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